Document Management Service (BC-SRV-KPR) 
Purpose
The Document Management Service (DMS) is a service of the information management infrastructure provided by the Knowledge Provider within the framework of SAP Web Application Server. The central task of the DMS is to process documents and document-like objects on the basis of application-specific content models. Only the DMS can modify document administration data and save this data in a storage medium, such as the SAP database.
Implementation Considerations
In order to use the DMS, you need to implement some Customizing steps: For details, see the Implementation Guide (IMG) 
Application Server 
Basis Services Knowledge Provider Document Management Service 
. The IMG modules contain details on the individual Customizing activities.
Features
The DMS provides the following functions:
Administration of attributes
Administration of relationships
An important task of the DMS is to shield the SAP applications from the details of administration data storage. In other words, the DMS takes care of the administration and processing of all administration data and the corresponding tables on behalf of the SAP applications.
The DMS also provides a lock mechanism. The lock mechanism guarantees that only one author can work on a document at any one time.
The DMS also has its own Programming Interface.